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Mechanochemistry provides synthetic access to MIL-53 type materials and reveals the relationship between metal–ligand reversibility and crystallite size.

The synthesis and characterization of two new porphyrin-based porous organic polymers (POPs) via Sonogashira cross-coupling reaction and leverage the two obtained POPs is reported for the fabrication of electrochemical aptasensors to detect kanamycin at an ultratrace level. The resultant electrochemical aptasensor demonstrates a high linear relationship with the logarithmic value of kanamycin concentration in the range 5 × 10⁻⁵–5 μg/L with the limit of detection of 17.6 pg/L or 36.3 fM. During the analysis of real samples from milk and river, a relative standard deviation of less than 4.39%, and good recovery values in the range 97.0–105% were obtained.

Graphical Abstract

A photoactive porphyrinic metal−organic framework (MOF) has been prepared by exchanging Ti into a Zr‐based MOF precursor. The resultant mixed‐metal Ti/Zr porphyrinic MOF demonstrates much‐improved efficiency for gas‐phase CO₂photoreduction into CH₄and CO under visible‐light irradiation using water vapor compared to the parent Zr‐MOF. Insightful studies have been conducted to probe the photocatalysis processes. This work provides the first example of gas‐phase CO₂photoreduction into methane without organic sacrificial agents on a MOF platform, thereby paving an avenue for developing MOF‐based photocatalysts for application in CO₂photoreduction and other types of photoreactions.

Described for the first time is that carbon dioxide (CO₂) can be successfully inserted into aryl C−H bonds of the backbone of a metal–organic framework (MOF) to generate free carboxylate groups, which serve as Brønsted acid sites for efficiently catalyzing the methanolysis of epoxides. The work delineates the very first example of utilizing CO₂for heterogeneous C−H activation and carboxylation reactions on MOFs, and opens a new avenue for CO₂chemical transformations under mild reaction conditions.

Herein, we report that a new flexible coordination network,NiL₂(L=4‐(4‐pyridyl)‐biphenyl‐4‐carboxylic acid), with diamondoid topology switches between non‐porous (closed) and several porous (open) phases at specific CO₂and CH₄pressures. These phases are manifested by multi‐step low‐pressure isotherms for CO₂or a single‐step high‐pressure isotherm for CH₄. The potential methane working capacity ofNiL₂approaches that of compressed natural gas but at much lower pressures. The guest‐induced phase transitions ofNiL₂were studied by single‐crystal XRD, in situ variable pressure powder XRD, synchrotron powder XRD, pressure‐gradient differential scanning calorimetry (P‐DSC), and molecular modeling. The detailed structural information provides insight into the extreme flexibility ofNiL₂. Specifically, the extended linker ligand,L, undergoes ligand contortion and interactions between interpenetrated networks or sorbate–sorbent interactions enable the observed switching.